Evolving appendicitis presenting as culture-negative peritonitis with minimal symptoms in a patient on continuous...

Culture-negative peritonitis, which results from a variety of etiologies, such as problems in culture techniques, prior use of antibiotics, infection caused by unusual organisms, and noninfectious causes, accounts for up to 20% of cases of peritonitis in peritoneal dialysis patients and sometimes poses diagnostic and therapeutic dilemmas. A 62-year-old woman on continuous ambulatory peritoneal dialysis (CAPD) presented with minimal abdominal pain and a turbid dialysate. Under the impression of infectious peritonitis, empirical intraperitoneal (IP) antibiotic treatment was administered. All cultures from the effluent were negative, although the white blood cell count in the effluent was elevated. Despite initial clinical improvement and resolution of abdominal pain, mild fever persisted, even after removal of the CAPD catheter. The first CT scan before removal of the catheter demonstrated no evidence of intra-abdominal pathology, except for the possibility of peritonitis, but a follow-up CT scan after removal of the catheter demonstrated a perforated appendix with a peri-appendiceal abscess. The patient recovered completely after removal of the appendix and the abscess. This case suggests that a follow-up CT scan and/or surgical exploration should be considered to identify the intra-abdominal pathology in patients with culture-negative refractory peritonitis, even after removal of CAPD catheter.